1. Field
The present invention is related to voltage regulation and control for use in electronic circuits.
2. Related Art
A voltage regulator circuit can provide a fixed and regulated output voltage when the input voltage supply is not constant (i.e., when the input voltage supply varies or fluctuates). A 1.5V voltage regulator can provide a fixed 1.5V supply when the input changes from 3V to 5V, for example. Voltage regulation is essential for systems that require a fixed and well-defined supply voltage while the input voltage supply (e.g., a battery) fluctuates, has ripples, is variable, and/or is noisy. In a conventional 1.5V voltage regulator, for example, the input voltage supply needs to be at least 1.5V higher than the desired output voltage of 1.5V (i.e., the input voltage supply needs to be at least 3V). In some applications, however, the input voltage supply can drop to values as low as 1.7V, causing variation in the output voltage.
Other important concerns include maintaining low power and current consumption and minimizing die area used. The accuracy of a voltage regulator is mainly determined by its bandgap circuit, or local reference generator circuit, although some inaccuracy can be attributed to its buffer circuit as well. For very good accuracy, the bandgap circuit needs to be large and/or consume higher power.
Therefore, what is needed is a low-power low-drop-out voltage regulator that uses a small die area and is capable of keeping power and current consumption low while maintaining accuracy and stability.